Toro Groundsmaster 4500-D Series - Page 136

PTODisengaged(continued)
g308182
Figure51
DECKCONTROLMANIFOLD(GM4700-D)
PTOEngaged
WhenthePTOswitchisturnedONwiththedeckslowered,thesolenoidvalves
(PRV1andPRV2)areenergizedwithoutputsfromtheTECcontroller(T1).The
energizedvalvesshifttodirectpumpowtowardthedeckmotors.Ascircuit
pressuretothedeckmotorsincreases,thebrakereliefcartridge(RV)opens
whichallowsanoilowthroughthemanifoldoricepositionedbeforethelogic
cartridge(LC).Thisowcreatesapressureincreaseatthelogiccartridgethat
willshiftthelogiccartridgeandallowoilreturnfromthedeckmotors.
OntheGroundsmaster4700-D(Figure51),ifdeck6ordeck7isloweredand
thePTOswitchisON,thedeckcontrolmanifoldsolenoidvalve(SV1/SV2)will
beenergizedbytheTECcontroller.Thisenergizedsolenoidvalveallowsoilow
totheappropriatedeckmotorasdescribedabove.
Maximummowcircuitpressureislimitedateachdeckmanifoldcircuitbythe
proportionalreliefvalve(PRV1/PRV2).Thedeckreliefvalvepressureis241
bar(3500PSI).MowcircuitpressurecanbemeasuredatportG1orG3ofthe
deckcontrolmanifold.
Thebrakereliefandlogiccartridgescontrolthestoppingrateofthebladeswhen
thesolenoidvalvesarede-energizedasthePTOswitchisturnedOFForifthe
decksareraised(seeCuttingDeckBladeBraking(page5–35)).
HydraulicSystem:HydraulicFlowDiagrams
Page5–34
Groundsmaster
®
4500-D/4700-D
19245SLRevA